If you do get a side effect, it's usually mild and will go away when you stop taking lansoprazole.

Common side effects of lansoprazole

These common side effects of lansoprazole may happen in more than 1 in 100 people. There are things you can do to help cope with them:

Headaches

Make sure you rest and drink plenty of fluids. It's best not to drink too much alcohol. Ask your pharmacist to recommend a painkiller.

Headaches usually go away after the first week of taking lansoprazole. Talk to your doctor if they do not go away or are severe.

Feeling or being sick (nausea or vomiting)

Stick to simple meals and do not eat rich or spicy food.

If you're being sick, try small frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee.

If you take the combined pill or progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Diarrhoea

Drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.

If you take the combined pill or progestogen-only pill and you have severe, watery diarrhoea or diarrhoea that lasts for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Stomach pain

Try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your stomach may also help. If you are in a lot of pain, speak to your pharmacist or doctor.

Constipation

Get more fibre into your diet such as fresh fruit, vegetables and cereals, and drink plenty of water. Try to exercise more regularly, for example, by going for a daily walk or run.

Farting

Try not to eat foods that cause wind like lentils, peas, beans and onions. It might also help to eat smaller and more frequent meals, eat and drink slowly, and exercise regularly. Some pharmacy remedies, such as simeticone, may help relieve the symptoms of wind.

Itchy or mild rash

It may help to take an antihistamine which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you.

Feeling dizzy or tired

If lansoprazole makes you feel dizzy or tired, stop what you're doing and sit or lie down until you feel better. Do not drive, cycle or use tools or machinery if you're feeling tired. Do not drink alcohol as it will make you feel worse.

Dry mouth or throat

Try chewing sugar-free gum or sucking sugar-free sweets.

Talk to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.

Serious side effects

Serious side effects are rare and happen in less than 1 in 1,000 people.

Call a doctor or call 111 straight away if you have:

stomach pain that seems to be getting worse, the whites of your eyes turn yellow or your skin turns yellow (this may be less obvious on brown or black skin), or dark pee – this can be a sign of an inflamed pancreas or liver
joint pain along with a red skin rash, especially on parts of your body exposed to the sun, such as your arms, cheeks and nose (this may be less obvious on brown or black skin) – these can be signs of a rare condition called subacute cutaneous lupus erythematosus. This can happen even if you've been taking lansoprazole for a long time
severe or persistent diarrhoea – this can be a sign of an inflamed bowel

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to lansoprazole.

Immediate action required: Call 999 now if:

your lips, mouth, throat or tongue suddenly become swollen
you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
your throat feels tight or you're struggling to swallow
your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
you suddenly become very confused, drowsy or dizzy
someone faints and cannot be woken up
a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

Do not drive yourself to A&E.

The person you speak to at 999 will give you advice about what to do.

Long-term side effects

If you take lansoprazole for more than 3 months, the levels of magnesium in your blood may fall.

This can make you feel tired, confused and dizzy, and cause muscle twitches, shaking and an irregular heartbeat. Contact your doctor or call 111 now if you get any of these symptoms.

Taking lansoprazole for more than 1 year may increase your chances of certain side effects, including:

bone fractures
gut infections
vitamin B12 deficiency – symptoms include feeling very tired, a sore and red tongue, mouth ulcers and pins and needles

If you take lansoprazole for longer than 1 year your doctor will regularly check your health to see if you should carry on taking it.

Lansoprazole can sometimes make it harder to notice the symptoms of stomach cancer.  It's therefore important that you contact your doctor if you have any new symptoms, if your symptoms change, or if anything does not feel normal for you.

Other side effects

These are not all the side effects of lansoprazole. For a full list see the leaflet inside your medicine packet.

Reporting side effects

You can report any suspected side effect using the Yellow Card safety scheme.

Visit the Yellow Card website for more information about reporting side effects.

Side effects of lansoprazole - Brand name: Zoton FasTabs